This invention relates to turbine engines and more particularly to a turbine engine using a differential gear to drive the fan and compressor.
A gas turbine engine, such as a turbo fan engine for an aircraft, includes a fan section, a compression section, a combustion section and a turbine section. An axis of the engine is centrally disposed within the engine and extends longitudinally through the sections. The core air flow path extends axially through the sections of the engine. A bypass air flow path extends parallel to and radially outward of the core air flow path.
The fan section includes a plurality of radially extending fan blades. The fan blades extend through the bypass flow path and interact with the air and transfer energy between the blades and air. A fan case circumscribes the fan in close proximity to the tips of the fan blades.
During operation, the fan draws the air into the engine. The fan raises the pressure of the air drawn along the bypass air flow path, thus producing useful thrust. The air drawn along the core air flow path into the compressor section is compressed. The compressed air is channeled to the combustion section where fuel is added to the compressed air and the air/fuel mixture is burned. The products of combustion are discharged to the turbine section. The turbine section extracts work from these products to power the fan and compressed air. Any energy from the products of combustion not needed to drive the fan and compressor contributes to useful thrust.
In the known turbine engines, the turbine section drives the fan and the compressor at fixed relative rates. However this may not be the ideal power/speed split during all conditions.